Draw the line as a polyline.
Change the linetype to hidden or dashed.
Change the LTSCALE as required so it looks like you want. I assume you are not using AutoCAD's model/paper space paradigm.
You could also create a layer (for example) named DASHED. Define the layer linetype as dashed, and what ever color you would like. Now every time you want to draw a dashed line, switch to that layer and the lines you draw will be dashed. You could do that for any linetypes you want (Center, Phantom, etc...). Just another alternative.
"Everybody is ignorant, only on different subjects." — Will Rogers
